Originally Posted by
viion
If done correctly I think you could see it being a neat addition but not overpowering, for example: Job Specific (Maybe as a Third Eye type of effect? on SAM Class), Cannot be shared, the job cannot get a self Heal so it relies on it, thus PLD which can self heal and has huge DEF down be still suitable. And you cannot add the skill as its job specific.
No common strategy used SAM to tank with Third Eye XD
Balance, I dont know about, Balance is such a strong word to talk about, GW2 has an Utsusemi type skill for Necromancer but you summon an actual copy of yourself, so to the NPC (or even player) its an identical clone of you and takes your spot, it even fights lol but its a fake shadow. Its quite deadly in PVP but its Balanced.